(a) Field of the Invention
The present invention relates to a Schottky barrier diode that includes silicon carbide (SiC) and a method for manufacturing the Schottky barrier diode.
(b) Description of the Related Art
Recently, as size and capacity of applications increase, a need for power semiconductor devices having a high breakdown voltage, a high current, and a rapid switching characteristic has increased. Among the power semiconductor devices, a Schottky barrier diode (SBD) using a Schottky junction, in which a metal and a semiconductor form a junction, without using a P-N junction unlike a general PN diode represents the rapid switching characteristic and has a turn-on voltage characteristic lower than the P-N diode.
The Schottky barrier diode requires a substantially low turn-on resistance or a substantially low saturation voltage to reduce a power loss in a conduction state while providing a flow of substantially large current. Further, the Schottky barrier diode requires a characteristic that withstands a reverse high voltage of the P-N junction which is applied across the Schottky barrier diode in a turn-off state or at the moment that a switch is turned-off, that is, a high breakdown voltage characteristic.
It is known that the breakdown voltage is affected by a curvature of a depletion region and in a planar junction, an edge portion having a curvature less than that of a flat portion of a junction portion is crowded with an electric field due to an electric field crowding effect which crowds an electric field around a portion having a curvature less than that of the flat junction portion. Therefore, a breakdown phenomenon readily occurs at the edge portion and the breakdown voltage determined by the entire depletion region is reduced.
The Schottky barrier diode is formed to have a mesa structure to increase the breakdown voltage by relieving the phenomenon that the electric field is crowded around the edge portion of the junction portion and reducing a surface electric field. The Schottky barrier diode having the mesa structure does not require a termination structure for ion implantation, and the like but requires an etching process to form the mesa structure. In particular, the characteristics of the Schottky barrier diode may deteriorate due to an interface defect during the etching process.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.